In March, the monthly output of molten iron of the second and third blast furnaces at Jingtang reached 802,200 tons, and the average utilization factor of the two blast furnaces reached 2.35, setting a new record of the production of double furnaces.

In March, the first blast furnace was overhauled as planned, and the second and third blast furnaces were in service at full capacity during the month. While working hard to implement prevent and control strategies during the COVID-19 epidemic, they continued to overhaul the first blast furnace and “get an A” in environmental protection. The Iron-making Department focused on the smoothness and stability of online production and achieved a historical breakthrough.

Since February, the Iron-making Department has set the goal of strengthening the operations guarantee of non-overhauling production lines and striving to reach the output target of 800 thousand tons. In blast furnaces’ operation, it has unified thinking, adhered to the principles of “attack, defense and retreat”, strengthened process control, predicted the trends in furnace conditions and made control adjustments in advance. On the basis of stabilizing the quality of the molten iron, the technicians had improved the gas distribution by optimizing the basic system of blast furnaces, and optimized the refueling system according to the changes in the quality of the original fuel to ensure that the central gas opening was within a reasonable range. In terms of full entry air rate, air temperature level, and oxygen-enriched rate, the two blast furnaces further had strengthened smelting by means of expanding selection of ore batches, increasing oxygen-enriched rate and improving gas. The main technical and economic indicators had been steadily improved. In March, the average fuel ratio of the two blast furnace reached 489 kg / ton. The Iron-making Department had conducted technical researches and realized a triple iron smelting blast furnace production mode. By adopting measures that include mud amount optimization, sectionalized mud production under pressure and the operating pressure optimization, the shallow furnace door problem was solved, and the average iron notch depth and the daily average tapping times were significantly increased. The Iron-making Department not only activated the furnace, improved the gas distribution, but also reduced the pressure difference in the furnace and improved the adaptability of the blast furnace tapping. Production operation was thus made more stable, which lays the foundation for the blast furnace to increase production and achieve greater efficiency.

In terms of raw fuel, guided by the integration of “research, supply, and production”, Shougang has always promoted the improvement of coke quality and reduction of ore consumption to ensure the smooth production of blast furnaces. Combined with the blast furnace’s demand for charge, the Iron-making Department actively took the lead in various aspects including entry charge quality assurance, quality monitoring and position control to strengthen the monitoring of alkali metals, management of coke size, and distribution management of the transitional material. They also established a tracking mechanism for raw fuel quality weekly reports, strengthened the inspection tracking management of raw fuel entering the factory, being stored in the warehouse and the raw fuel entity, and improved the stable organization and guarantee capabilities of the incoming charge. In order to solve the phenomenon of pellets cracking during the pelletizing process, pellet technicians adopted measures like using low-controlling mixture and raw pellet moisture, appropriately adjusting the amount of bentonite, stabilizing the machine speed and the amount of raw pellets entering the machine to ensure the quality of the finished pellets. Pellets’ cracking was stabilized from 25% to less than 13%.

The equipment point inspectors kept their eyes fixed on the goal of “ensuring smoothness and stability”. They strengthened the equipment operating management and control, clarified the management responsibilities by improving the equipment system management methods, and effectively integrated the maintenance units, production posts, point inspection and professional management forces. The entire workforce participated in equipment management, ensuring the smooth and stable production of the blast furnaces. On March 12, three blast furnaces began to smelt iron three times. In order to ensure the smooth tapping, the blast furnace point inspection area strengthened the slag flushing equipment before the furnaces in a unified manner. After the three machines before the furnaces stopped working, their maintenance was to be completed within one week, with special point inspections carried out when work commences, guaranteeing production will run smoothly. In view of the high temperature environment of the three machines before the furnaces, spray cooling was added to the oil-cylinders and hoses of the groove cover machine, which reduced the faults on the line. For critical equipment such as belt conveyors in the slag flushing area, preventive maintenance and repairs were carried out by using the tapping gap, laying a solid foundation for the long-term smoothness and stability of the blast furnaces.